Welding power supplies, wire feeders, and systems to compensate a weld voltage via communications over a weld circuit

ABSTRACT

Methods and apparatus to communicate via a weld cable are disclosed. An example weld circuit communications device includes a receiver circuit, a processor, and a local communications adapter. The receiver circuit to receive a communication via a weld circuit while current is flowing through the weld circuit or after the current has stopped flowing through the weld circuit, the communication including weld voltage feedback information measured at a device remote from a power supply and remote from the weld circuit communications device while the current is flowing through the weld circuit. The processor generates power supply control information based on the weld voltage feedback information. The local communications adapter transmits the power supply control information to control welding-type power output by a power converter to regulate a weld voltage to a weld voltage setpoint.

BACKGROUND

The invention relates generally to welding systems, and moreparticularly to welding power supplies, wire feeders, and systems tocompensate a weld voltage via communications over a weld circuit.

Some welding applications, such as coal-fired boiler repair, shipyardwork, and so forth, may position a welding location or workpiece largedistances from a multi-process welding power source. The power sourceprovides conditioned power for the welding application, and the weldermust pull and monitor a long welding power cable extending from thepower source to the welding location. Accordingly, the location of powerterminals (e.g., plugs) and controls on or proximate to the weldingpower source may require the user to stop welding and return to thepower source to plug in auxiliary devices, make changes to the weldingprocess, and so forth. In many applications, this may entail walkingback considerable distances, through sometimes complex and intricatework environments. Additionally, weld cables (and, particularly, longweld cables) introduce a non-negligible voltage drop between the powersource and the site of the work (e.g., the wire feeder, the torch).

Accordingly, there exists a need for systems and methods for providingaccurate weld voltages that correspond to the weld voltages set on theweld equipment, and particularly without requiring additionalcommunications cables or using wireless communications equipment thatcan be unreliable in a weld environment.

SUMMARY

Welding power supplies, wire feeders, and systems to compensate a weldvoltage via communications over a weld circuit are disclosed,substantially as illustrated by and described in connection with atleast one of the figures, as set forth more completely in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example welding-type system in accordance with aspectsof this disclosure.

FIG. 2 is a block diagram of an example voltage feedback control loopthat may be implemented by the controller of FIG. 1 to control a powerconverter in accordance with aspects of this disclosure.

FIG. 3 shows another example welding-type system in accordance withaspects of this disclosure.

FIG. 4 is a flowchart illustrating example machine readable instructionswhich may be executed by the example welding-type power supply of FIG. 1to compensate welding output voltage in accordance with aspects of thisdisclosure.

FIGS. 5A and 5B illustrate a flowchart illustrating example machinereadable instructions which may be executed by the example controller ofFIG. 1 to determine an adjustment to a weld voltage output by the powersupply and/or the power converter to regulate a weld voltage to a weldvoltage setpoint in accordance with aspects of this disclosure.

FIG. 6 is a flowchart illustrating example machine readable instructionswhich may be executed by the example wire feeder of FIG. 1 to compensatewelding output voltage in accordance with aspects of this disclosure.

FIG. 7 is a flowchart illustrating example machine readable instructionswhich may be executed by the example wire feeder of FIG. 3 to compensatewelding output voltage in accordance with aspects of this disclosure.

FIG. 8 illustrates another example welding system including weldcommunications adapters in accordance with aspects of this disclosure.

DETAILED DESCRIPTION

Weld cable communications enable components of welding systems, such asa welding power supply and a wire feeder, to communicate via a samecable used to deliver welding current from the power supply to the wirefeeder (and to a welding torch attached to the wire feeder). Weld cablecommunications enable a simplification of a welding system by, forexample, removing one or more cables that were conventionally used forcontrol signals.

Disclosed examples provide for a voltage sensing wire feeder for weldingthat enables a welding power supply to adjust an arc voltage (e.g., avoltage across an arc, between the electrode and the workpiece) tocompensate for the voltage drop over the weld cable between the weldingpower supply and a remote wire feeder. As used herein, the term “remote”refers to not being in a same physical enclosure. For example, a wirefeeder that is separate from a welding power supply (e.g., connected tothe welding power supply by a weld cable) is considered a remote wirefeeder for the purposes of this disclosure.

In some examples, a remote wire feeder measures the arc voltage andcommunicates the arc voltage to the power supply via the weld circuit asweld voltage feedback information while the weld circuit is conductingweld current (e.g., during a weld operation), which enables the powersupply to adjust the voltage and/or current output by the power supply.For example, the power supply may adjust the voltage and/or current toreduce or minimize a difference between the actual (e.g., measured) arcvoltage and a weld voltage setpoint. In some other examples, the remotewire feeder stores the voltage measurements in an internal memory andtransmits the voltage measurements to the power supply when the weldingoperation has completed.

Disclosed example power supplies execute a weld voltage control loop,and use the voltage measurements from the remote wire feeder as afeedback mechanism in the control loop to adjust the output power. Insome examples, the power supply calculates a profile of the weld cableand/or the weld circuit, which is used during subsequent welds tocompensate the output power to result in the arc voltage beingsubstantially equal to the weld voltage setpoint. Thus, disclosedexamples provide more predictable and reliable weld voltages to awelder.

Some conventional power supplies and welders communicate using controlcables that are separate from the weld circuit. However, such controlcables are fragile, expensive, and cause additional hazards in a weldingenvironment, particularly when there are relatively long distances(e.g., 100 feet or more) between the power supply and the remote wirefeeder. Disclosed examples enable voltage compensation by the powersupply without the requirement of additional control cables or wirelesscommunications that are unreliable in electrically noisy weldingenvironments.

As used herein, the term “port” refers to one or more terminals(s),connector(s), plug(s), and/or any other physical interface(s) fortraversal of one or more inputs and/or outputs. Example ports includeweld cable connections at which a weld cable is physically attached to adevice, a gas hose connector connectors that may make physical and/orelectrical connections for input and/or output of electrical signalsand/or power, physical force and/or work, fluid, and/or gas.

As used herein, the term “welding-type power” refers to power suitablefor welding, plasma cutting, induction heating, CAC-A and/or hot wirewelding/preheating (including laser welding and laser cladding). As usedherein, the term “welding-type power supply” refers to any devicecapable of, when power is applied thereto, supplying welding, plasmacutting, induction heating, CAC-A and/or hot wire welding/preheating(including laser welding and laser cladding) power, including but notlimited to inverters, converters, resonant power supplies,quasi-resonant power supplies, and the like, as well as controlcircuitry and other ancillary circuitry associated therewith.

As used herein, a “weld voltage setpoint” refers to a voltage input tothe power converter via a user interface, network communication, weldprocedure specification, or other selection method.

As used herein, a “circuit” includes any analog and/or digitalcomponents, power and/or control elements, such as a microprocessor,digital signal processor (DSP), software, and the like, discrete and/orintegrated components, or portions and/or combinations thereof.

As used herein, the term “weld circuit” includes any and all componentsin an electrical path of a welding operation, regardless whether thewelding operation is underway. For example, the weld circuit isconsidered to include any or all of: power conversion and/orconditioning component(s), weld cable conductor(s), weld torch(es),consumable or non-consumable welding electrode(s), workpiece(s), workclamp(s), ground cable(s) (return cables), weld cable connections (e.g.,weld studs that connect a welding power supply to a weld cable). As usedherein, the “weld circuit” does not include components or conductorsthat do not conduct weld current at any time (i.e., that are not in theelectrical path of the weld current). For example, the weld circuit doesnot include separate control cables that transmit data but do nottransmit weld current.

As used herein, the term “filtering,” as it applies to voltage and/orcurrent values, refers to generating one or more representative valuesfrom a larger set of values. For example, a set of voltage values ormeasurements may be filtered to obtain an average voltage, aroot-mean-square value of the voltage values, or any otherrepresentative or derivative value(s).

Disclosed example welding-type power supplies include a power converter,a receiver circuit, and a controller. The power converter converts inputpower to welding-type power based on a weld voltage setpoint and tooutput the welding-type power via a weld circuit. The receiver circuitreceives a communication via the weld circuit while current is flowingthrough the weld circuit or after the current has stopped flowingthrough the weld circuit. The communication includes weld voltagefeedback information measured at a device remote from the power supplywhile the current is flowing through the weld circuit. The controllercontrols the welding-type power output by the power converter accordingto a voltage feedback loop using the weld voltage feedback informationto regulate a weld voltage at the remote device to the weld voltagesetpoint.

In some examples, the controller is configured to control a voltage ofthe welding-type power output by the power converter according to thevoltage feedback loop by adjusting the welding-type power while thecurrent is being output through the weld circuit. In some examples, thecontroller is configured to control the voltage of the welding-typepower output by the power converter according to the voltage feedbackloop by adjusting a voltage compensation value applied to thewelding-type power based on the weld voltage setpoint and a measuredvoltage included in the weld voltage feedback information. Thecontroller stores the voltage compensation value for generating thewelding-type power for a subsequent weld. In some such examples, thecontroller is configured to adjust the voltage of the welding-type poweroutput by the power converter based on the voltage compensation valueduring the subsequent weld. In some examples, the controller isconfigured to control the voltage of the welding-type power output bythe power converter based on a plurality of communications received viathe weld circuit. The plurality of communications corresponding to aplurality of voltage measurements. In some such examples, the controlleris configured to store the plurality of voltage measurements that aretaken at the remote device and at the power supply and that correspondto at least one of power supply output voltage measurements or weldingcurrent measurements. The controller determines the voltage compensationvalue based on the at least one of the power supply output voltagemeasurements or the welding current measurements.

Some example welding-type power supplies further include a power sourcevoltage monitor to measure an actual power source output voltage. Thecontroller executes the voltage feedback loop using the weld voltagefeedback information, the weld voltage setpoint, and the actual powersource output voltage. In some such examples, the weld voltage feedbackinformation comprises a filtered arc voltage of the welding-type powermeasured at a wire feeder. The power source voltage monitor determines afiltered power supply output voltage of the welding-type power measuredat an output terminal of the welding-type power supply, and thecontroller adjusts the weld voltage of the welding-type power based on adifference between the filtered arc voltage and the filtered powersupply output voltage. In some examples, the controller controls thevoltage of the welding-type power by determining an adjusted weldvoltage setpoint based on the weld voltage setpoint and the differencebetween the filtered arc voltage and the filtered power supply outputvoltage. In some such examples, the controller adjusts the welding-typepower based on a difference between the adjusted weld voltage setpointand the filtered power supply output voltage.

In some example welding-type power supplies, the controller adjusts thewelding-type power at a first rate and the receiver circuit isconfigured to receive the weld voltage feedback information at a secondrate that may be different than the first rate (e.g., slower than thefirst rate). The controller adjusts the welding-type power at the firstrate based on a most recently received weld voltage feedbackinformation. In some examples, the weld voltage feedback informationcomprises a voltage error between the voltage setpoint and a voltagemeasured at the device remote from the power supply while the current isflowing through the weld circuit, and the controller controls thewelding-type power output using the voltage error. In some suchexamples, the controller calculates an impedance of a weld cable in theweld circuit using the voltage error.

In some examples, the weld voltage feedback information includes acharacteristic of a weld cable that is part of the weld circuit, and thecontroller controls the welding-type power output using thecharacteristic. In some such examples, the characteristic comprises acalculated impedance of the weld cable. In some example welding-typepower supplies, the weld voltage feedback information includes a voltagesetpoint command, and the controller controls the welding type poweroutput using the voltage setpoint command by controlling the powerconverter to output the welding-type power having a voltage determinedby the voltage setpoint command. Additionally or alternatively, the weldvoltage feedback information may include information that can be used tocalculate the weld cable characteristic (e.g., measured weld voltagefeedback from a wire feeder). In an example, a power supply receives aset of arc voltage feedback samples and calculates a weld cableimpedance using the arc voltage feedback samples in conjunction withcorresponding voltage setpoints and current measurements determined atthe power supply.

Disclosed example welding-type power supplies include a power converter,a voltage monitor, a receiver circuit, and a controller. The powerconverter converts input power to welding-type power based on auser-selected voltage and outputs the welding-type power via a weldcircuit. The voltage monitor measures a power supply output voltage ofthe welding-type power during a weld. The receiver circuit receives, viathe weld circuit while current is flowing through the weld circuit orafter the current has stopped flowing through the weld circuit, acommunication including a measured arc voltage of the welding-type powermeasured at a first location in the weld circuit different than a secondlocation at which the voltage monitor is to measure the power supplyoutput voltage. When the communication including the measured arcvoltage is received during the weld, the controller adjusts thewelding-type power during the weld to reduce a difference between theuser-selected voltage and the measured arc voltage based on the powersupply output voltage. When the communication including the measured arcvoltage is received after the weld, the controller adjusts a voltagecompensation value applied to the welding-type power based on theuser-selected voltage, the power supply output voltage, and the measuredarc voltage, and stores the voltage compensation value for generatingthe welding-type power for a subsequent weld.

In some examples, the controller stores the voltage compensation valuebased on the measured arc voltage measured during a first weld, andadjusts the welding-type power based on the voltage compensation valueduring the subsequent weld. In some such examples, the controllerdetermines the voltage compensation value based on a plurality ofcommunications received via the weld circuit, where the plurality ofcommunications corresponds to a plurality of arc voltage measurements.In some examples, the controller stores power supply output voltagemeasurements and/or weld current measurements corresponding to theplurality of arc voltage measurements, and determines the voltagecompensation value based on the power supply output voltage measurementsand/or the weld current measurements and the arc voltage measurements.In some examples, the voltage compensation value may be determined bycalculating a weld cable impedance and/or by performing a lookup of arcvoltage measurements, power supply output voltage measurements and/orweld current measurements in a table.

In some example welding-type power supplies, the power supply outputvoltage is a filtered power supply output voltage of the welding-typepower measured at a weld circuit output terminal of the power converter,and the measured arc voltage is a filtered arc voltage of thewelding-type power measured at a wire feeder. The controller increases avoltage of the welding-type power based on a difference between thefiltered power supply output voltage and the filtered arc voltage. Insome such examples, the controller adjusts the welding-type power at afirst rate and the receiver circuit receives measurements of themeasured arc voltage at a second rate. The controller calculates thedifference at the second rate and adjust the welding-type power at thefirst rate based on a most recent calculation of the filtered arcvoltage. In some examples, the second rate is different than the firstrate.

In some examples, the controller adjusts the voltage of the welding-typepower by determining an adjusted weld voltage setpoint based on theuser-selected voltage and the difference between the filtered powersupply output voltage and the filtered arc voltage. In some suchexamples, the controller adjusts the voltage of the welding-type powerbased on a difference between the adjusted weld voltage setpoint and thefiltered power supply output voltage.

Disclosed example welding-type power supplies include a power converterto convert input power to welding-type power based on a weld voltagesetpoint and to output the welding-type power via a weld circuit, areceiver circuit to receive voltage feedback information without the useof a separate data transmission cable connection or a voltage sense leadconnection, and a controller to control a voltage of the welding-typepower output by the power converter according to a voltage feedback loopusing the weld voltage feedback information and the weld voltagesetpoint.

In some examples, the receiver circuit receives the voltage feedbackinformation further without the use of wireless communications. In someexamples, the receiver circuit receives the voltage feedback informationvia the weld circuit.

Disclosed example welding devices include a voltage monitor and a weldcable communication transmitter. The voltage monitor measures a weldvoltage of welding-type power received via a weld circuit during awelding-type operation. The weld cable communication transmittertransmits, via the weld circuit during output of the welding-type power,a communication based on the weld voltage of the welding-type power, orstores the weld voltage in a memory and transmits the communication viathe weld circuit after output of the welding-type power has stopped.

Some example welding devices further include a user interface to receivea user selection of a voltage setpoint, where the weld cablecommunication transmitter transmits a second communication indicative ofthe user selection of the voltage setpoint. Some such examples furtherinclude a controller to determine a voltage setpoint command based onthe voltage setpoint and the weld voltage, where the weld cablecommunication transmitter transmits the voltage setpoint command via theweld circuit. Some examples include a controller to determine animpedance of a weld cable in the weld circuit and to determine theimpedance based on the voltage setpoint, the weld voltage, and a currentof the welding-type power. Some examples include a controller todetermine a voltage error as a difference between the voltage setpointand the weld voltage, where the weld cable communication transmittertransmits the voltage error via the weld circuit.

Some example welding devices further include a voltage filter circuit toprovide a filtered value of the weld voltage over a time period, wherethe weld cable communication transmitter identifies the filtered valuein the communication. Some example welding devices further include aweld cable communications receiver to receive a voltage setpoint, and acontroller to determine an impedance of a weld cable connected to theweld circuit, where the controller determines the impedance based on thevoltage setpoint, the weld voltage, and a current of the welding-typepower. Some example welding devices further include a weld cablecommunications receiver to receive a voltage setpoint, and a controllerto determine a voltage error as a difference between the voltagesetpoint and the weld voltage, where the weld cable communicationtransmitter transmits the voltage error via the weld circuit. In someexamples, the welding device is a wire feeder or a pendant controldevice.

Disclosed example welding-type power supplies include a power converterto convert input power to welding-type power based on a weld voltagesetpoint and to output the welding-type power via a weld circuit, and areceiver circuit to receive a communication via the weld circuit whilecurrent is flowing through the weld circuit or after the current hasstopped flowing through the weld circuit. The communication includesweld voltage feedback information measured at a device remote from thepower supply while the current is flowing through the weld circuit. Theexample welding-type power supplies further include a display device todisplay the weld voltage feedback information while the current isflowing through the weld circuit.

Disclosed example welding devices include a voltage monitor to measure avoltage of welding-type power received via a weld circuit during awelding-type operation, a display device to display the weld voltage,and a weld cable communication transmitter to transmit, via the weldcircuit during output of the welding-type power, a communicationrepresentative of the weld voltage of the welding-type power.

Disclosed example weld circuit communications devices include a receivercircuit, a processor, or a local communications adapter. The receivercircuit receives a communication via a weld circuit while current isflowing through the weld circuit or after the current has stoppedflowing through the weld circuit. The communication includes weldvoltage feedback information measured at a device remote from a powersupply and remote from the weld circuit communications device while thecurrent is flowing through the weld circuit. The processor generatespower supply control information based on the weld voltage feedbackinformation. The local communications adapter to transmit the powersupply control information to control welding-type power output by apower converter to regulate a weld voltage to a weld voltage setpoint.

In some example weld circuit communications devices the power supplycontrol information includes at least one of a voltage setpoint, avoltage error, a weld cable impedance. Some example weld circuitcommunications devices further include a voltage monitor to measure apower supply output voltage. The weld voltage feedback informationincludes a remote voltage measured closer to the weld than the powersupply output voltage measurement location.

Some example weld circuit communications devices further include avoltage monitor to measure a power source output voltage. The processorgenerates the power supply control information using the weld voltagefeedback information, the weld voltage setpoint, and the measured powersource output voltage. In some such examples, the weld voltage feedbackinformation comprises a filtered arc voltage of the welding-type powermeasured at a wire feeder or a remote communications device, and thevoltage monitor determines a filtered power supply output voltage of thewelding-type power measured at an output of the power supply. Theprocessor adjusts a weld voltage of the welding-type power based on adifference between the filtered arc voltage and the filtered powersupply output voltage.

Some example weld circuit communications devices further include atransmitter to transmit weld information to the remote device via theweld circuit while the current is flowing through the weld circuit. Insome examples, the weld voltage feedback information includes a voltageerror between the voltage setpoint and a voltage measured at the deviceremote from the power supply and remote from the weld circuitcommunications device while the current is flowing through the weldcircuit. The processor generates the power supply control informationusing the voltage error. In some such examples, the processor isconfigured to calculate an impedance of a weld cable in the weld circuitusing the voltage error, where the power supply control informationincludes the impedance of the weld cable. In some examples, the weldvoltage feedback information includes a voltage setpoint command, andthe processor provides the voltage setpoint command for control of thepower supply to output the welding-type power having a voltagedetermined by the voltage setpoint command.

Disclosed weld circuit communications device includes a voltage monitorto measure a voltage of welding-type power transmitted via a weldcircuit during a welding-type operation, and a transmitter circuit totransmit, via the weld circuit during transmission of the welding-typepower over the weld circuit, weld voltage feedback information based onthe weld voltage of the welding-type power.

Some example weld circuit communications devices further include a localcommunications adapter to receive a voltage setpoint from a weldingdevice. Some example weld circuit communications devices further includea processor to determine a voltage setpoint command based on a voltagesetpoint and the weld voltage, the transmitter circuit configured totransmit the voltage setpoint command via the weld circuit. In someexamples, the transmitter circuit is configured to transmit the voltagesetpoint via the weld circuit during transmission of the welding-typepower over the weld circuit.

Some example weld circuit communications devices further include aprocessor to determine an impedance of a weld cable in the weld circuitbased on the voltage setpoint, the weld voltage, and a current of thewelding-type power, the transmitter circuit configured to transmit theimpedance via the weld circuit. Some example weld circuit communicationsdevices further include a processor to determine a voltage error as adifference between the voltage setpoint and the weld voltage, thetransmitter circuit to transmit the voltage error via the weld circuit.

Disclosed example weld circuit communications devices include a localcommunications adapter to receive weld voltage feedback information froma welding device on a first interface, and a transmitter circuit totransmit, via a weld circuit during transmission of welding-type powerover the weld circuit, the weld voltage feedback information based onthe weld voltage of the welding-type power.

In some examples, the local communications adapters receives a voltagemeasurement, and the example weld circuit communications device furtherincludes a processor to generate the weld voltage feedback informationfrom the voltage measurement. In some examples, the local communicationsadapter receives a voltage setpoint from the welding device and thetransmitter circuit transmits the voltage setpoint via the weld circuitduring transmission of the welding-type power over the weld circuit.

In some examples, the local communications adapter receives a voltagesetpoint from the welding device, the weld circuit communications devicefurther includes a processor to determine a voltage error as adifference between the voltage setpoint and the weld voltage, and thetransmitter circuit transmits the voltage error via the weld circuit. Insome examples, the weld circuit communications device further includes aprocessor to determine an impedance of a weld cable in the weld circuitbased on the voltage setpoint, the weld voltage, and a current of thewelding-type power, where the transmitter circuit transmits theimpedance via the weld circuit.

Turning now to the drawings, FIG. 1 is a block diagram of an examplewelding system 100 having a welding power supply 102, a wire feeder 104,and a welding torch 106. The welding system 100 powers, controls, andsupplies consumables to a welding application. In some examples, thewelding power supply 102 directly supplies input power to the weldingtorch 106. The welding torch 106 may be a torch configured for shieldedmetal arc welding (SMAW, or stick welding), tungsten inert gas (TIG)welding, gas metal arc welding (GMAW), flux cored arc welding (FCAW),based on the desired welding application. In the illustrated example,the welding power supply 102 is configured to supply power to the wirefeeder 104, and the wire feeder 104 may be configured to route the inputpower to the welding torch 106. In addition to supplying an input power,the wire feeder 104 may supply a filler metal to a welding torch 106 forvarious welding applications (e.g., GMAW welding, flux core arc welding(FCAW)). While the example system 100 of FIG. 1 includes a wire feeder104 (e.g., for GMAW or FCAW welding), the wire feeder 104 may bereplaced by any other type of remote accessory device, such as a stickwelding and/or TIG welding remote control interface that provides stickand/or TIG welding

The welding power supply 102 receives primary power 108 (e.g., from theAC power grid, an engine/generator set, a battery, or other energygenerating or storage devices, or a combination thereof), conditions theprimary power, and provides an output power to one or more weldingdevices in accordance with demands of the system 100. The primary power108 may be supplied from an offsite location (e.g., the primary powermay originate from the power grid). The welding power supply 102includes a power converter 110, which may include transformers,rectifiers, switches, and so forth, capable of converting the AC inputpower to AC and/or DC output power as dictated by the demands of thesystem 100 (e.g., particular welding processes and regimes). The powerconverter 110 converts input power (e.g., the primary power 108) towelding-type power based on a weld voltage setpoint and outputs thewelding-type power via a weld circuit.

In some examples, the power converter 110 is configured to convert theprimary power 108 to both welding-type power and auxiliary poweroutputs. However, in other examples, the power converter 110 is adaptedto convert primary power only to a weld power output, and a separateauxiliary converter is provided to convert primary power to auxiliarypower. In some other examples, the welding power supply 102 receives aconverted auxiliary power output directly from a wall outlet. Anysuitable power conversion system or mechanism may be employed by thewelding power supply 102 to generate and supply both weld and auxiliarypower.

The welding power supply 102 includes a controller 112 to control theoperation of the welding power supply 102. The welding power supply 102also includes a user interface 114. The controller 112 receives inputfrom the user interface 114, through which a user may choose a processand/or input desired parameters (e.g., voltages, currents, particularpulsed or non-pulsed welding regimes, and so forth). The user interface114 may receive inputs using any input device, such as via a keypad,keyboard, buttons, touch screen, voice activation system, wirelessdevice, etc. Furthermore, the controller 112 controls operatingparameters based on input by the user as well as based on other currentoperating parameters. Specifically, the user interface 114 may include adisplay 116 for presenting, showing, or indicating, information to anoperator. The controller 112 may also include interface circuitry forcommunicating data to other devices in the system 100, such as the wirefeeder 104. For example, in some situations, the welding power supply102 wirelessly communicates with other welding devices within thewelding system 100. Further, in some situations, the welding powersupply 102 communicates with other welding devices using a wiredconnection, such as by using a network interface controller (NIC) tocommunicate data via a network (e.g., ETHERNET, 10baseT, 10base100,etc.). In the example of FIG. 1, the controller 112 communicates withthe wire feeder 104 via the weld circuit via a communicationstransceiver 118, as described below.

The controller 112 includes at least one controller or processor 120that controls the operations of the welding power supply 102. Thecontroller 112 receives and processes multiple inputs associated withthe performance and demands of the system 100. The processor 120 mayinclude one or more microprocessors, such as one or more“general-purpose” microprocessors, one or more special-purposemicroprocessors and/or ASICS, and/or any other type of processingdevice. For example, the processor 120 may include one or more digitalsignal processors (DSPs).

The example controller 112 includes one or more storage device(s) 123and one or more memory device(s) 124. The storage device(s) 123 (e.g.,nonvolatile storage) may include ROM, flash memory, a hard drive, and/orany other suitable optical, magnetic, and/or solid-state storage medium,and/or a combination thereof. The storage device 123 stores data (e.g.,data corresponding to a welding application), instructions (e.g.,software or firmware to perform welding processes), and/or any otherappropriate data. Examples of stored data for a welding applicationinclude an attitude (e.g., orientation) of a welding torch, a distancebetween the contact tip and a workpiece, a voltage, a current, weldingdevice settings, and so forth.

The memory device 124 may include a volatile memory, such as randomaccess memory (RAM), and/or a nonvolatile memory, such as read-onlymemory (ROM). The memory device 124 and/or the storage device(s) 123 maystore a variety of information and may be used for various purposes. Forexample, the memory device 124 and/or the storage device(s) 123 maystore processor executable instructions 125 (e.g., firmware or software)for the processor 120 to execute. In addition, one or more controlregimes for various welding processes, along with associated settingsand parameters, may be stored in the storage device 123 and/or memorydevice 124, along with code configured to provide a specific output(e.g., initiate wire feed, enable gas flow, capture welding currentdata, detect short circuit parameters, determine amount of spatter)during operation.

In some examples, the welding power flows from the power converter 110through a weld cable 126 to the wire feeder 104 and the welding torch106. The example weld cable 126 is attachable and detachable from weldstuds at each of the welding power supply 102 and the wire feeder 104(e.g., to enable ease of replacement of the weld cable 126 in case ofwear or damage). Furthermore, in some examples, welding data is providedwith the weld cable 126 such that welding power and weld data areprovided and transmitted together over the weld cable 126. Thecommunications transceiver 118 is communicatively coupled to the weldcable 126 to communicate (e.g., send/receive) data over the weld cable126. The communications transceiver 118 may be implemented based onvarious types of power line communications methods and techniques. Forexample, the communications transceiver 118 may utilize IEEE standardP1901.2 to provide data communications over the weld cable 36. In thismanner, the weld cable 126 may be utilized to provide welding power fromthe welding power supply 102 to the wire feeder 104 and the weldingtorch 106. Additionally or alternatively, the weld cable 126 may be usedto transmit and/or receive data communications to/from the wire feeder104 and the welding torch 106. The communications transceiver 118 iscommunicatively coupled to the weld cable 126, for example, via cabledata couplers 127, to characterize the weld cable 126, as described inmore detail below. The cable data coupler 127 may be, for example, avoltage or current sensor.

The example communications transceiver 118 includes a receiver circuit121 and a transmitter circuit 122. Generally, the receiver circuit 121receives data transmitted by the wire feeder 104 via the weld cable 126and the transmitter circuit 122 transmits data to the wire feeder 104via the weld cable 126. As described in more detail below, thecommunications transceiver 118 enables remote configuration of the powersupply 102 from the location of the wire feeder 104 and/or compensationof weld voltages by the power supply 102 using weld voltage feedbackinformation transmitted by the wire feeder 104. In some examples, thereceiver circuit 121 receives communication(s) via the weld circuitwhile weld current is flowing through the weld circuit (e.g., during awelding-type operation) and/or after the weld current has stoppedflowing through the weld circuit (e.g., after a welding-type operation).Examples of such communications include weld voltage feedbackinformation measured at a device that is remote from the power supply102 (e.g., the wire feeder 104) while the weld current is flowingthrough the weld circuit.

Example implementations of the communications transceiver 118 aredescribed in U.S. Pat. No. 9,012,807. The entirety of U.S. Pat. No.9,012,807 is incorporated herein by reference. However, otherimplementations of the communications transceiver 118 may be used.

The example wire feeder 104 also includes a communications transceiver119, which may be similar or identical in construction and/or functionas the communications transceiver 118.

In some examples, a gas supply 128 provides shielding gases, such asargon, helium, carbon dioxide, and so forth, depending upon the weldingapplication. The shielding gas flows to a valve 130, which controls theflow of gas, and if desired, may be selected to allow for modulating orregulating the amount of gas supplied to a welding application. Thevalve 130 may be opened, closed, or otherwise operated by the controlcircuitry 22 to enable, inhibit, or control gas flow (e.g., shieldinggas) through the valve 130. Shielding gas exits the valve 130 and flowsthrough a cable 132 (which in some implementations may be packaged withthe welding power output) to the wire feeder 104 which provides theshielding gas to the welding application. In some examples, the weldingsystem 100 does not include the gas supply 128, the valve 130, and/orthe cable 132.

In some examples, the wire feeder 104 uses the welding power to powerthe various components in the wire feeder 104, such as to power a wirefeeder controller 134. As noted above, the weld cable 126 may beconfigured to provide or supply the welding power. The welding powersupply 102 may also communicate with a communications transceiver 119 ofthe wire feeder 104 using the weld cable 126 and the communicationstransceiver 118 disposed within the welding power supply 102. In someexamples, the communications transceiver 119 is substantially similar tothe communications transceiver 118 of the welding power supply 102. Thewire feeder controller 134 controls the operations of the wire feeder104. In some examples, the wire feeder 104 uses the wire feedercontroller 134 to detect whether the wire feeder 104 is in communicationwith the welding power supply 102 and to detect a current weldingprocess of the welding power supply 102 if the wire feeder 104 is incommunication with the welding power supply 102.

A contactor 135 (e.g., high amperage relay) is controlled by the wirefeeder controller 134 and configured to enable or inhibit welding powerto continue to flow to the weld cable 126 for the welding application.In some examples, the contactor 135 is an electromechanical device.However, the contactor 135 may be any other suitable device, such as asolid state device. The wire feeder 104 includes a wire drive 136 thatreceives control signals from the wire feeder controller 134 to driverollers 138 that rotate to pull wire off a spool 140 of wire. The wireis provided to the welding application through a torch cable 142.Likewise, the wire feeder 104 may provide the shielding gas from thecable 132 through the cable 142. The electrode wire, the shield gas, andthe power from the weld cable 126 are bundled together in a single torchcable 144 and/or individually provided to the welding torch 106.

The welding torch 106 delivers the wire, welding power, and/or shieldinggas for a welding application. The welding torch 106 is used toestablish a welding arc between the welding torch 106 and a workpiece146. A work cable 148 couples the workpiece 146 to the power supply 102(e.g., to the power converter 110) to provide a return path for the weldcurrent (e.g., as part of the weld circuit). The example work cable 148attachable and/or detachable from the power supply 102 for ease ofreplacement of the work cable 148. The work cable 148 may be terminatedwith a clamp 150 (or another power connecting device), which couples thewelding power supply 102 to the workpiece 146.

The example wire feeder 104 of FIG. 1 includes a voltage monitor 152coupled to the weld circuit (e.g., electrically connected to the weldcable 126) and to the workpiece 146 via a clamp 154 and a sense lead156. The example voltage monitor 152 may be coupled to the weld circuitvia a cable data coupler 127. The voltage monitor 152 measures a weldvoltage, such as the voltage between the output to the torch 106 (e.g.,at a weld output connector or stud to which the cable 144 is connectedto electrically connect the torch 106 to the wire feeder 104) and theworkpiece 146 (e.g., via the sense lead 156). Because the wire feeder104 is significantly closer to the arc than the power supply 102 is tothe arc, the voltage measured at the wire feeder 104 is not affected bythe impedance of the weld cable 126. As a result, the measurementscaptured by the voltage monitor 152 can be considered to berepresentative of the arc voltage.

The voltage monitor 152 captures one or more measurements (e.g.,samples) of the weld voltage (e.g., the arc voltage, the voltage betweenthe torch 106 and the workpiece 146). In some examples, the voltagemonitor 152 assigns time stamps to the measurements for use inperforming calculations, compensation, and/or matching of measurementsto other measurements.

The example voltage monitor 152 and/or the controller 134 performfiltering (e.g., analog and/or digital filtering) to determine arepresentative value of the voltage over a designated time period. Therepresentative value may be a filtered voltage value based on themeasurements captured by the voltage monitor 152, such as an averagevoltage over the designated time period or a root-mean-square voltageover the designated time period. For example, the voltage monitor 152and/or the controller 112 may calculate an average weld voltage for an Nsecond time period based on a corresponding number of measurementscaptured by the voltage monitor 152 at a designated rate. In someexamples, the time period for filtering is selected based on theswitching frequency of the power converter 110 and/or a processingfrequency used by the controller 134 and/or the processor(s) 120.

The example controller 134 stores the average weld voltage(s) and/or thevoltage measurement(s) as weld voltage feedback information. Thecommunications transceiver 119 transmits the weld voltage feedbackinformation to the power supply 102 via the weld circuit (e.g., via theweld cable 126). The communications transceiver 119 may transmit theweld voltage feedback information while the weld circuit is conductingwelding current (e.g., during a welding operation and/or while an arc ispresent between the torch 106 and the workpiece 146) and/or after thewelding current is finished (e.g., at the conclusion of the weldingoperation during which the voltage monitor 152 captured the voltagemeasurements).

In some examples, the weld voltage feedback information includes acharacteristic of the weld cable 126 such as a model number or otheridentifier of the weld cable 126 that can be used to accuratelycompensate the weld voltage for the drop over the weld cable 126. Forexample, if a model of weld cable has a determinable impedance withoutmeasurements, the controller 112 can use the identification of that weldcable to compensate the output from the power converter 110.

When the welding power supply 102 receives the voltage measurements, thepower supply 102 updates a voltage feedback loop for controlling thepower converter 110. The voltage feedback loop may be executed by theexample controller 112 of FIG. 1. An example voltage feedback loop is acontrol algorithm that controls an output voltage using an input valueand which is responsive to the output voltage and/or an intermediatesignal associated with the output voltage. The controller 112 controlsthe welding-type power output by the power converter 110 according to avoltage feedback loop using the weld voltage feedback information toregulate the voltage at the remote device (e.g., at the wire feeder 104)to the weld voltage setpoint. For example, the controller 112 may usedata received from the wire feeder 104 via the weld circuit to controlthe weld voltage at the arc to substantially equal the voltage setpoint(e.g., to compensate for the voltage drop caused by the weld cable 126).

The example power supply 102 includes a voltage monitor 160 thatmeasures an actual power source output voltage. The actual power sourceoutput voltage is an approximation that is substantially equal to, butmay be slightly different (e.g., a negligible difference) than, the realvoltage that is output from the power source to the weld cable 126. Thecontroller 112 may execute a feedback loop using the actual power sourceoutput voltage as an input. In some examples, the voltage monitor 160 isincluded in the power converter 110.

In some examples, the controller 112 receives an average arc voltage ofthe welding-type power measured at the wire feeder 104, and the voltagemonitor 160 determines an average output voltage of the welding-typepower measured at an output terminal of the power supply 102. Thecontroller 112 adjusts a weld voltage of the welding-type power based ona difference between the average arc voltage and the average powersupply output voltage.

In some examples, the voltage feedback loop is a constant voltage (CV)or voltage-controlled control loop. The example controller 112calculates a current adjustment using a set of measurable and/orderivable voltage values.

As mentioned above, the weld cable 126 between the power supply 102 andthe wire feeder 104 causes a voltage drop. The voltage drop caused bythe weld cable 126 (V_(cabledrop)) can be expressed as a differencebetween a voltage measured at the power supply output (e.g., V_(stud),measured across the power supply output studs or ports) and a voltagemeasured at the wire feeder 104 (e.g. V_(feeder)), as expressed inEquation 1 below. The V_(feeder) term is received as the weld voltagefeedback information, such as a weld voltage measurement and/or averageweld voltage determined by the wire feeder 104 and communicated via theweld cable 126.V _(cableDrop) =V _(stud) −V _(feeder)  Equation 1

Adjusting the voltage output by the power converter 110 (e.g., V_(stud))by the voltage drop in the weld cable 126 (e.g., V_(cableDrop))effectively raises the voltage at the wire feeder 104 (e.g.,V_(feeder)). Thus, the example controller 112 may adjust the power(e.g., voltage and/or current) output by the power converter 110 tocause the voltage at the wire feeder 104 (e.g., effectively the weldvoltage or arc voltage) to substantially match a voltage setpoint.

The example controller 112 adjusts the voltage setpoint (e.g., V_(cmd))to determine an adjusted voltage setpoint V_(adjustedcmd) (e.g., anadjusted voltage command) according to Equation 2 below.V _(AdjustedCmd) =V _(cmd) +V _(cableDrop)  Equation 2

When the power supply 102 receives an average voltage measurement fromthe wire feeder 104 and generates average voltage measurements via thevoltage monitor 160, the controller 112 controls the voltage of thewelding-type power by determining an adjusted weld voltage setpoint(e.g., V_(AdjustedCmd)) based on the weld voltage setpoint (e.g.,V_(cmd)) and the difference between the average arc voltage and theaverage power supply output voltage (e.g., an average V_(cabledrop)).

An error term V_(error) may be calculated by the relationship shown inEquation 3 below.V _(error)=(V _(AdjustedCmd) −V _(stud))  Equation 3

By implementing Equation 3, the controller 112 may adjust thewelding-type power based on a difference between the adjusted voltagesetpoint and the average power supply output voltage. In the example ofFIGS. 1 and 2, V_(error) is used directly in calculating a new currentcommand. If the adjusted voltage error is not used, calculating theoutput of the power converter 110, that output will not converge to anexpected solution.

The example equations may be implemented by the controller 112 tocontrol the voltage of the welding-type power output by the powerconverter 110 according to the voltage feedback loop by adjusting avoltage compensation value (e.g., V_(error)) applied to the welding-typepower based on the weld voltage setpoint (e.g., V_(cmd)) and a measuredvoltage included in the weld voltage feedback information (e.g.,V_(feeder)). In some examples, the controller 112 stores the voltagecompensation value for generating the welding-type power for subsequentwelding-type operations. The controller 112 may then adjust the voltageof the welding-type power output by the power converter 110 based on thevoltage compensation value during the subsequent weld.

The controller 112 may control the voltage of the welding-type poweroutput by the power converter 110 based on multiple communicationsreceived via the weld circuit, where the multiple communicationscorrespond to multiple voltage measurements (e.g., V_(feeder) values) bythe wire feeder 104. For example, the controller 112 may store multiplepower supply voltage measurements (e.g., V_(stud) values) and/or weldcurrent measurements that correspond to the plurality of voltagemeasurements (e.g., V_(feeder) values) and determine the voltagecompensation value based on the weld voltage measurements, the powersupply output voltage measurements and/or the weld current measurements.The voltage compensation value may be determined by calculating animpedance of the weld cable 126 and/or by performing a lookup of weldvoltage measurements, power supply output voltage measurements and/orweld current measurements in a table stored in the storage device 125and/or in the memory 124.

In some examples, the control equation implemented by the controller 112is executed with a first execution rate (e.g., 20 kHz, or one commandupdate every 50 μs, while the weld voltage feedback information (e.g.,V_(feeder)) is up dated at a second rate that may be limited by the weldcable bandwidth (e.g., 2 Hz, or one weld voltage update every 500,000μs). The different update rates result in a multi-rate control system,in which reported voltage data from the wire feeder 104 that could besampled or delivered at any point during a welding operation is used ina higher-speed control loop.

The example controller 112 avoids an unstable control loop situationcaused by the data update rate mismatch and non-uniform network dataarrival (e.g., variable sampling interval) by: 1) using low-passfiltered data for the voltage setpoint V_(cmd) and the weld voltagefeedback information V_(feeder) to calculate the weld cable voltage dropV_(cableDrop) and the adjusted voltage setpoint V_(AdjustedCmd); 2)calculating the adjusted voltage setpoint V_(AdjustedCmd) when a validweld voltage feedback information V_(feeder) arrives via the weld cable126 and use the most recently calculated value for the adjusted voltagesetpoint V_(AdjustedCmd) (e.g., until the next weld voltage feedbackinformation arrives and a new value for the adjusted voltage setpoint iscalculated); and 3) on start-up of the welding power supply, setting theadjusted voltage setpoint V_(AdjustedCmd) to a maximum allowed value ofthe adjusted voltage setpoint V_(AdjustedCmd) and allowing the system toadjust to the actual measured voltage drops.

In some examples, the controller 112 controls the voltage of thewelding-type power output by the power converter according to thevoltage feedback loop by adjusting the welding-type power while the weldcurrent is being output through the weld circuit (e.g., instead ofmaking adjustments between welds). Additionally or alternatively, thecontroller 112 makes the adjustments between welding operations (e.g.,adjusts a voltage for a subsequent welding operation to compensate for avoltage error observed during a prior welding operation).

In some examples, the display 116 displays the weld voltage feedbackinformation, such as the measured weld voltage, for real-time viewing ofthe actual weld voltage by an operator or other viewer of the powersupply 102. Additionally, the user interface 114 may permit selection ofthe weld voltage and/or the power supply output voltage for display onthe display device 116. By displaying (or permitting display) of thereal-time weld voltage during the weld, the operator, supervisor, and/orany other interested viewer can be assured that the weld voltagespecified by the user is the weld voltage at the arc. Such assurance maybe useful for verifying compliance with a weld procedure specification.

FIG. 2 is a block diagram of an example voltage feedback control loop200 that may be implemented by the controller 112 of FIG. 1 to controlthe power converter 110. For example, the controller 112 may implementthe control loop 200 by executing the instruction 125. The control loop200 receives a voltage setpoint 202 as an input and generates a weldoutput power 204 that has substantially the same voltage as the voltagesetpoint 202.

In the control loop 200, the voltage setpoint 202 is added to a weldcable voltage drop 206 using a summer 208. The weld cable voltage drop206 is determined at a summer 210 as a difference between a wire feedervoltage 212 and a voltage 214 sensed at the power converter 110. Thewire feeder voltage 212 is substantially identical to the voltage of theweld output power 204, and may incur a communications delay 216 thatcontrols the use of the wire feeder voltage 212 and/or the weld cablevoltage drop 206 in the control loop 200 (e.g., the summer 208 mayreceive the weld cable voltage drop 206 at a rate that is different thanthe execution rate of the control loop 200).

The summer 208 outputs a voltage error 218 to a voltage regulator 220.The voltage regulator 220 receives the voltage error 218, the voltage214 sensed at the power converter 110, and a current 222 sensed at thepower converter 110. The voltage regulator 220 outputs a power convertercommand 224 based on the voltage error 218, the voltage 214 sensed atthe power converter 110, and the current 222 sensed at the powerconverter 110. The power converter command 224 controls the powerconverter 110 to generate an output power 226. The power converter 110outputs the output power 226 to the weld cable 126, which has acorresponding weld cable impedance 228 in the control loop 200, and to awelding arc 230. The voltage 214 sensed at the power converter 110 andthe current 222 sensed at the power converter 110 are measuredsubstantially at the output of the power converter 110 to the weld cable126.

FIG. 3 shows another example welding-type system 300. The welding-typesystem 300 includes the power supply 102 and the wire feeder 104 ofFIG. 1. In contrast with the example system 100 of FIG. 1, in thewelding-type system 300 the controller 134 implements portions of acontrol loop, such as the control loop 200 of FIG. 2 and/or the controlscheme described above with respect to Equations 1-3, to control a weldvoltage at the output of the wire feeder 104 to be substantially equalto a voltage setpoint. The example controller 134 includes a processor302, a memory device 304, a storage device 306, and/or computer readableinstructions 308.

In the example system 300 of FIG. 3, the wire feeder 104 receives thevoltage setpoint from the welding power supply 102 (e.g., via thecommunications transceivers 118, 119 and the weld cable 126) and/or viaa user interface 310 of the wire feeder 104. The controller 134determines a difference between a measured weld voltage (e.g., from thevoltage monitor 152 and the voltage setpoint.

As in the system 100 of FIG. 1, the controller 134 feeds backinformation to the power supply 102 to enable the power supply 102 toadjust the voltage output by the power converter 110. For example, bydetermining a difference between the voltage measured at the wire feeder104 and the voltage setpoint, the wire feeder 104 can feed back adifference or error value for use by the power supply 102.

In some examples, the wire feeder 104 executes the control loop todetermine a voltage command, and communicates the voltage command to thepower supply 102 (e.g., using the communications transceiver 119) to beimplemented by the power supply 102 to achieve the setpoint voltage atthe weld voltage. The power supply 102 implements the commanded voltageby outputting the commanded voltage to the weld cable 126. In suchexamples, the wire feeder 104 has knowledge of the current voltagecommand at the power supply. As such, the example wire feeder 104 maymeasure a current flowing through the weld cable 126 and use thecurrent, the voltage command, and the voltage measured at the wirefeeder 104 to characterize the impedance of the weld cable 126.

FIG. 4 is a flowchart illustrating example machine readable instructions400 which may be executed by the example welding-type power supply 102of FIG. 1 to compensate welding output voltage. The example instructions400 may be stored in the storage device(s) 123 and/or the memory 124,and/or executed by the controller 112 of FIG. 1.

At block 402, the power supply 102 is turned on and the weld cable 126is connected to a weld cable port. At block 404, the controller 112determines whether a voltage adjustment has been received. For example,controller 112 may identify a change to a voltage setpoint received viathe user interface 114. If a voltage adjustment has been received (block404), at block 406 the controller 112 sets the weld voltage setpoint.

After setting the weld voltage setpoint (block 406), or if a voltageadjustment has not been received (block 404), at block 408, thecontroller 112 determines whether a weld voltage feedback informationhas been received from a remote device (e.g., the remote wire feeder 104of FIG. 1). For example, the controller 112 may receive the weld voltagefeedback information from the communications transceiver 118 and/or thereceiver circuit 121, which extracts the weld voltage feedbackinformation from the weld circuit including the weld cable 126. If theweld voltage feedback information has been received from the remotedevice (block 408), at block 410 the controller 112 stores the weldvoltage feedback information (e.g., in the storage device(s) 123, in thememory 124). The stored weld voltage feedback information may include,for example, a voltage measured at the wire feeder 104 that isrepresentative of the weld voltage, a voltage error term identifying adifference between the remotely measured voltage and a voltage setpoint,a voltage output command, and/or any other voltage feedback informationthat may be used by the power supply 102 to control the output of thepower converter 110 to set the weld voltage substantially equal to thevoltage setpoint. The stored weld voltage feedback information mayreplace a previously stored weld voltage feedback information and/or maybe appended as a most recent weld voltage feedback information.

After storing the weld voltage feedback information (block 410), atblock 412, the controller determines whether weld power is being outputby the power converter 110. For example, the controller 112 may measurethe current output by the power converter 110 to determine whether thecurrent is greater than a threshold. If the weld power is not beingoutput (block 412), control returns to block 404.

When the weld power is being output (block 412), at block 414 thecontroller 112 controls the power converter 110 to output the weld poweraccording to the selected weld voltage setpoint and/or a selectedcurrent setpoint. For example, the controller 112 may execute thecontrol loop 200 of FIG. 2 and/or the control loop described above withreference to Equations 1-3.

At block 416, the controller 112 measures and output voltage at outputstuds of the power supply 102 and stores the output voltage in thememory device 124. For example, the controller 112 may receive themeasurement of the output voltage from the voltage monitor 160. At block418, the controller 112 determines an adjustment to the weld voltageand/or the weld current output by the power converter 110 based on thestored weld feedback voltage information, to regulate the weld voltageto the weld voltage setpoint. For example, the controller 112 mayexecute a feedback loop to compensate for the voltage drop across theweld cable 126 between the power supply 102 and the remote wire feeder104. The controller 112 may receive additional weld voltage feedbackinformation via the weld circuit while a welding operation is occurringand repeatedly adjust the output voltage from the power converter 110 tocontrol the weld voltage to the weld voltage setpoint. Exampleinstructions to implement block 418 are described below with referenceto FIGS. 5A-5B.

At block 420, the controller 112 adjusts the weld voltage output by thepower converter 110 based on the adjustment (determined in block 418).Control then returns to block 404.

As mentioned above, in the example instructions 400 of FIG. 4, thecontroller 112 may receive weld voltage feedback information via theweld circuit while weld power is being output and/or after weld powerhas been stopped.

FIGS. 5A and 5B illustrate a flowchart illustrating example machinereadable instructions which may be executed by the example controller112 of FIG. 1 to determine an adjustment to a weld voltage output by thepower supply 102 and/or the power converter 110 to regulate a weldvoltage to a weld voltage setpoint. The example instructions 500 ofFIGS. 5A-5B may be executed by the controller 112 of FIG. 1 to implementblock 418 of FIG. 4.

The instructions 500 enter from block 416 of FIG. 4. At block 502, thecontroller 112 determines whether the weld voltage feedback information(e.g., received via the weld circuit, the communications transceiver118, and/or the receiver circuit 121) includes a filtered measured weldvoltage. For example, the weld voltage feedback information may includea voltage value representative of an average (or median, orroot-mean-square, or any other representative value) voltage measured ata remote device such as the wire feeder 104 of FIG. 1. An example isdescribed below with reference to an average voltage value.

When the weld voltage feedback information includes a filtered weldvoltage measurement (block 502), at block 504 the controller 112determines a filtered power supply output voltage for a time periodcorresponding to the filtered measured weld voltage. For example, thecontroller 112 may store measurements of the voltage output by the powerconverter 110 in the storage device(s) 123 and/or the memory 124, andcalculate the average of the voltage measurements during the time periodrepresented by the weld voltage feedback information. In some examples,the weld voltage feedback information includes a timestamp or otherindicator of the time period for which the filtered voltage measurementsapply.

At block 506, the controller 112 determines a weld cable voltage drop asthe difference between the filtered measured weld voltage and thefiltered power supply output voltage. Block 506 may implement Equation 1above. At block 508, the controller 112 determines an adjusted voltagesetpoint as a sum of the weld cable voltage drop and the voltagesetpoint. Block 508 may implement Equation 2 above. At block 510, thecontroller 112 calculates an adjustment to the weld voltage and/or theweld current output by the power converter 110 using the adjustedvoltage setpoint. Block 510 may implement Equation 3 above. After block510, the example instructions 500 end and/or return control to a callingfunction, such as block 418 of FIG. 4 to use the adjustment to controlthe power converter 110 using the instructions 400 of FIG. 4.

When the weld voltage feedback information does not include a filteredweld voltage measurement (block 502), at block 512 the controller 112determines whether the weld voltage feedback information includes avoltage error. For example, the wire feeder 104 or other remote devicemay calculate a voltage error term and transmit the voltage error termto the power supply 102 via the weld circuit (e.g., while weld power isbeing output by the power converter 110 to the weld circuit). When theweld voltage feedback information includes a voltage error (block 512),at block 514, the controller 112 calculates an adjustment to the weldvoltage and/or the weld current output by the power converter 110 usingthe voltage error.

After block 514, the example instructions 500 end and/or return controlto a calling function, such as block 418 of FIG. 4 to use the adjustmentto control the power converter 110 using the instructions 400 of FIG. 4.

Turning to FIG. 5B, when the weld voltage feedback information does notinclude a voltage error (block 512), at block 516 the controller 112determines whether the weld voltage feedback information includes a weldcable impedance (block 516). For example, the wire feeder 104 maycalculate a weld cable impedance based on knowledge of the voltage beingoutput by the power supply 102, the weld current, and the voltagemeasured at the wire feeder 104. If the weld voltage feedbackinformation includes a weld cable impedance (block 516), at block 518the controller measures (or otherwise determines) an output current fromthe power converter 110.

In some examples, the controller 112 may calculate the weld cableimpedance using the weld voltage feedback information (e.g., voltagemeasurements at the wire feeder 104, a voltage error term, etc.) andmeasurements of the voltage and current output by the power converter110 to the weld cable 126.

At block 520, the controller 112 determines a voltage drop over the weldcable 126 as the product of multiplying the output current and the weldcable impedance. At block 522, the controller 112 determines an adjustedvoltage setpoint as a sum of the weld cable voltage drop and the voltagesetpoint. Block 522 may implement Equation 2 above. At block 524, thecontroller 112 calculates an adjustment to the weld voltage and/or theweld current output by the power converter 110 using the adjustedvoltage setpoint. Block 524 may implement Equation 3 above. After block524, the example instructions 500 end and/or return control to a callingfunction, such as block 418 of FIG. 4 to use the adjustment to controlthe power converter 110 using the instructions 400 of FIG. 4.

If the weld voltage feedback information does not include a weld cableimpedance (block 516), at block 526 the controller 112 determineswhether the weld voltage feedback information includes a voltagesetpoint command. For example, the voltage setpoint command may bedetermined and provided to the power supply 102 by the remote device(e.g., the wire feeder 104) via the weld circuit to enable the wirefeeder 104 to calculate a voltage setpoint and use the voltage setpointto control the power supply 102. If the weld voltage feedbackinformation includes a voltage setpoint command (block 526), at block528, the controller 112 calculates an adjustment to the weld voltageand/or weld current output by the power converter 110 based on adifference between the voltage setpoint command (from the wire feeder104) and the current voltage setpoint (used by the controller 112 tocontrol the power converter 110). After block 528 and/or if the weldvoltage feedback information does not include a voltage setpoint command(block 526), the example instructions 500 end and/or return control to acalling function, such as block 418 of FIG. 4 to use the adjustment tocontrol the power converter 110 using the instructions 400 of FIG. 4.

FIG. 6 is a flowchart illustrating example machine readable instructions600 which may be executed by the example wire feeder 104 of FIG. 1 tocompensate welding output voltage. For example, the controller 134 mayexecute the instructions 600 to provide weld voltage feedbackinformation to the power supply 102 via the weld circuit and/or thecommunications transceiver 119. While the example instructions 600 aredescribed below with reference to the wire feeder 104, the instructions600 may be used and/or modified to implement other remote weldingdevices.

At block 602, the weld cable 126 is connected to an input port (e.g.,input stud) of the wire feeder 104. At block 604, the controller 134determines whether a voltage setpoint adjustment has been received. Forexample, controller 134 may identify a change to a voltage setpointreceived via a user interface of the wire feeder 104. If a voltageadjustment has been received (block 604), at block 606 the controller134 sends the voltage setpoint adjustment to the power supply 102 viathe weld circuit and/or the transceiver 119.

After sending the voltage setpoint adjustment (block 606), or if avoltage setpoint adjustment has not been received (block 604), at block608, the controller 134 determines whether to transmit weld voltagefeedback information to the power supply 102. For example, thecontroller 134 may track a number of voltage measurement samples takenby the voltage monitor 152 and, when the number of samples satisfies athreshold, generate and transmit the weld voltage feedback information.Additionally or alternatively, the controller 134 may generate andtransmit the weld voltage feedback information in response to an event,such as a conclusion of a welding operation (e.g., detected as the weldcurrent falling below a threshold current). In some examples, thecontroller 134 may generate and transmit the weld voltage feedbackinformation based on a feedback frequency, which may be based on acommunication bandwidth (e.g., the communication bandwidth of the weldcircuit and the transceiver 119). In the example below, the weld voltagefeedback information includes a filtered measured weld voltage over anumber of samples and/or a time period. However, other weld voltagefeedback information may be transmitted, such as a differentrepresentative weld voltage value, a voltage error value between ameasured weld voltage and the weld voltage setpoint, a weld cablecharacteristic such as a calculated weld cable impedance or a weld cableidentifier, and/or a voltage setpoint command.

If a condition is met to transmit weld voltage feedback information tothe power supply 102 (block 608), at block 610 the voltage monitor 152and/or the controller 134 calculates a filtered weld voltage during avoltage compensation period based on a set of stored arc voltages (e.g.,in the memory 124 of the wire feeder 104). At block 612, thecommunications transceiver 119 transmits the filtered weld voltage tothe power supply 102 (e.g., via the weld circuit including the weldcable 126). The communications transceiver 119 may also transmit atimestamp or other indicator of the time period represented by thefiltered weld voltage. The timestamp may be used by the power supply tomatch the received weld voltage feedback information to voltagemeasurements taken by the voltage monitor 160 for comparison. In someexamples, the example controller 134 clears stored weld voltages to freestorage space for subsequent sampling. In some other examples,subsequent samples overwrite older samples in the memory 124.

After transmitting the filtered weld voltage (block 612), or iftransmitting weld voltage feedback information to the power supply 102is not performed (block 608), at block 614, the controller 134determines whether weld power is to be output to a weld operation. Forexample, the controller 134 may determine whether a trigger of the weldtorch 106 is depressed. If weld power is being output (block 614), atblock 616, the wire feeder 104 outputs the weld power received via theweld cable 126 to the weld torch 106 for a welding-type operation (e.g.,welding, wire preheating, workpiece preheating, etc.). The voltagemonitor 152 measures the weld voltage at an output to the weld torch 106and stores the measured voltage in the memory 124. Control then returnsto block 604.

FIG. 7 is a flowchart illustrating example machine readable instructions700 which may be executed by the example wire feeder of FIG. 3 tocompensate welding output voltage. For example, the controller 134 ofFIG. 3 may execute the instructions 700 to execute at least a portion ofa welding control loop, and to provide feedback and/or commands to thepower supply 102 via the weld circuit and/or the communicationstransceiver 119. While the example instructions 700 are described belowwith reference to the wire feeder 104, the instructions 700 may be usedand/or modified to implement other remote welding devices.

At block 702, the weld cable 126 is connected to an input port (e.g.,input stud) of the wire feeder 104. At block 704, the controller 134determines whether a voltage setpoint adjustment has been received. Forexample, controller 134 may identify a change to a voltage setpointreceived via a user interface 310 of the wire feeder 104. If a voltageadjustment has been received (block 704), at block 706 the controller134 sends the voltage setpoint adjustment to the power supply 102 viathe weld circuit and/or the transceiver 119.

After sending the voltage setpoint adjustment (block 706), or if avoltage setpoint adjustment has not been received (block 704), at block708 the controller 134 determines whether weld power is to be output toa weld operation. For example, the controller 134 may determine whethera trigger of the weld torch 106 is depressed. If weld power is to beoutput (block 708), at block 710 the wire feeder 104 outputs the weldpower received via the weld cable 126. At block 712, the voltage monitor152 measures the weld voltage at the output to the weld torch 106. Atblock 714, the controller 134 calculates a difference between thevoltage setpoint and the measured weld voltage as a voltage error. Atblock 716, the controller 134 stores the voltage error (e.g., in thememory 124).

After storing the voltage error (block 716), and/or if the weld power isnot being output (block 708), at block 718 the controller 134 determineswhether to transmit weld voltage feedback information. If the controller134 is to transmit the weld voltage feedback information (block 718), atblock 720 the controller 134 determines a voltage setpoint command basedon a voltage error and the voltage setpoint. For example, the controller134 may add the voltage error to the voltage setpoint to determine theadjusted command voltage to be used by the power supply 102 as an outputvoltage to the weld cable 126.

At block 722, the controller 134 determines an impedance of the weldcable 126 based on the voltage setpoint, the measured weld voltage, anda weld current. The weld current may be an actual weld current measuredat the wire feeder 104 and/or at the power supply 102. The examplecontroller 134 may determine weld cable impedance using Equation 4below, or any other method. In Equation 4 below, Z_(cable) is the weldcable impedance, V_(measured) is the measured weld voltage at the wirefeeder 104, V_(setpoint) is the voltage setpoint, and I_(measured) isthe weld current.Z _(cable)=(V _(setpoint) −V _(measured))/I _(measured)  Equation 4

At block 724, the controller 134 transmits (e.g., via the communicationstransceiver 119 and/or the weld circuit) the voltage error, the voltagesetpoint command, and/or the weld cable impedance to the power supply102 as weld voltage feedback information. For example, the controller134 may provide any or all of the voltage error, the voltage setpointcommand, and/or the weld cable impedance to the power supply 102 toenable the power supply 102 to make adjustments to control the weldvoltage to the voltage setpoint.

After transmitting the voltage error, the voltage setpoint command,and/or the weld cable impedance (block 724), or if transmission is notto occur (block 718), control returns to block 704.

FIG. 8 illustrates another example welding system 800. The examplewelding system 800 includes a power supply 802 and a wire feeder 804.The example power supply 802 is similar to the power supplies 102 ofFIGS. 1 and 3 and the wire feeder 804 is similar to the wire feeders 104of FIGS. 1 and 3. However, the example power supply 802 and the examplewire feeder 804 are not, by themselves, capable of communicating via aweld circuit. The example power supply 802 and the example wire feeder804 are provided with respective weld communication adapters 806, 808 toenable the system 800 to compensate a weld voltage for a voltage dropcaused by the weld cable 126 during a welding operation.

Each of the communications adapters 806, 808 includes processor(s) 120a, 120 b, storage device(s) 123 a, 123 b, memory 124 a, 124 b, and/orinstructions 125 a, 125 b, which may be similar, identical, or differentthan the processor(s) 120, storage device(s) 123, memory 124, and/orinstructions 125 of FIGS. 1 and 3. Each of the communications adapters806, 808 further includes a weld circuit transceiver 810 a, 810 b, whichmay include a receiver circuit 121 a, 121 b and/or a transmitter circuit122 a, 122 b. In some examples, one of the communications adapters 806,808 includes a receiver circuit 121 a, 121 b to receive data via a weldcircuit and the other of the communications adapters 806, 808 includes atransmitter circuit 122 a, 122 b to transmit the data. The receivercircuits 121 a, 121 b and/or the transmitter circuits 122 a, 122 b maybe similar, identical, or different than the receiver circuit 121 and/orthe transmitter circuit 122 of FIGS. 1 and 3. The weld cablecommunications adapters 806, 808 of FIG. 8 may be supplemented by otherforms of communications such as wireless (e.g., WiFi) communicationsmethods.

Each of the communications adapters 806, 808 further includes a voltagemonitor 812 a, 812 b and/or a local communications adapter 814 a, 814 b.The example voltage monitors 812 a, 812 b may be connected to the weldcircuit to measure voltages at different locations in the weld circuit.For example, the voltage monitor 812 a may be connected to outputterminals of the welding power supply 802 (e.g., on a first end of theweld cable) and the voltage monitor 812 b may be connected to inputterminals and/or output terminals of the wire feeder 804 (e.g., on anopposite end of the weld cable). The connections may be implementedusing terminal adapters connected between the ends of the weld cable 126and the power supply 802 and the wire feeder 804,

The example local communications adapters 814 a, 814 b are configured tocommunicate with the welding power supply 802 and the wire feeder 804using a serial or parallel communications port. Using the weldcommunications adapters 806, 808, welding devices such as the weldingpower supply 802 and/or the wire feeder 804 that are not configured forweld circuit communications may still take advantage of the benefits ofweld circuit communications including a reduced number of cablesextending from the welding power supply 802 to a remote device such as asuitcase wire feeder that may be hundreds of feet away.

The welding power supply 802 (e.g., the controller 112) and the localadapter 814 a communicates data and/or commands to provide weld voltagefeedback information to the welding power supply 802 for compensating aweld voltage, and/or to provide weld parameters and/or data to the wirefeeder 804 via the weld cable 126. Similarly, the local communicationsadapter 814 b communicates with the wire feeder 804 (e.g., thecontroller 134) to provide voltage information and/or commands from thewire feeder 804 to the power supply 802.

In an example of operation of the system 800, the receiver circuit 121 aof the communications adapter 806 receive a communication via the weldcircuit (e.g., the weld cable 126) while current is flowing through theweld circuit. The communication includes weld voltage feedbackinformation measured while the current is flowing through the weldcircuit at a device (e.g., the wire feeder 804, the weld communicationsadapter 808) that is remote from the power supply 802 and remote fromthe weld circuit communications device 806. For instance, the weldvoltage feedback information may be measured by the voltage monitor 812b and/or by the voltage monitor 158. The processor(s) 120 a generatespower supply control information based on the weld voltage feedbackinformation. Depending on the form of the weld voltage feedbackinformation, the processor(s) 120 a may do conversion of the weldvoltage feedback information to a voltage error, a voltage setpoint, aweld cable impedance, and/or any other control information. For example,the voltage monitor 812 a may measure a power supply output voltage atthe output of the welding power supply 802 when the weld voltagefeedback information including a remote voltage measured closer to theweld than the power supply output voltage measurement location.

The local communications adapter 814 a transmits the power supplycontrol information to the controller 112 of the welding power supply802 (e.g., via a direct serial or parallel connection) to enable thepower supply 802 to control welding-type power output by the powerconverter 110. Thus, the controller 112 may use information transmittedvia the weld circuit during a welding operation to regulate a weldvoltage of the welding operation to a weld voltage setpoint.

To provide the weld voltage feedback information to the power supply 802via the weld circuit, in some examples the voltage monitor 812 bmeasures a voltage of welding-type power transmitted via the weldcircuit during a welding-type operation (e.g., near the end of the weldcable 126 terminating at the wire feeder 804). The transmitter circuit122 b transmits, via the weld circuit during transmission of thewelding-type power over the weld circuit, the weld voltage feedbackinformation based on the voltage of the welding-type power. In someother examples, the local communications adapter 814 b receives weldvoltage feedback information from the controller 134 on a firstinterface such as a serial or parallel port, a wireless connection,and/or another local connection interface. The weld cable communicationtransmitter 122 b transmits the weld voltage feedback information (e.g.,to the weld communications adapter 806) via the weld circuit duringtransmission of the welding-type power over the weld circuit.

While FIG. 8 illustrates an example in which both the power supply 802and the wire feeder 804 are incapable of communicating over a weldcircuit (and particularly, while current is flowing in the weldcircuit), in some examples only one of the weld communications adapters806, 808 is used to provide weld circuit communication capabilities tothe welding power supply 802 or the wire feeder 804 when the other ofthe power supply 802 or the wire feeder 804 has weld circuitcommunications integrated.

The present methods and systems may be realized in hardware, software,and/or a combination of hardware and software. The present methodsand/or systems may be realized in a centralized fashion in at least onecomputing system, or in a distributed fashion where different elementsare spread across several interconnected computing systems. Any kind ofcomputing system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may include a general-purpose computing system with a programor other code that, when being loaded and executed, controls thecomputing system such that it carries out the methods described herein.Another typical implementation may comprise an application specificintegrated circuit or chip. Some implementations may comprise anon-transitory machine-readable (e.g., computer readable) medium (e.g.,FLASH drive, optical disk, magnetic storage disk, or the like) havingstored thereon one or more lines of code executable by a machine,thereby causing the machine to perform processes as described herein. Asused herein, the term “non-transitory machine-readable medium” isdefined to include all types of machine readable storage media and toexclude propagating signals.

As utilized herein the terms “circuits” and “circuitry” refer tophysical electronic components (i.e. hardware) and any software and/orfirmware (“code”) which may configure the hardware, be executed by thehardware, and or otherwise be associated with the hardware. As usedherein, for example, a particular processor and memory may comprise afirst “circuit” when executing a first one or more lines of code and maycomprise a second “circuit” when executing a second one or more lines ofcode. As utilized herein, “and/or” means any one or more of the items inthe list joined by “and/or”. As an example, “x and/or y” means anyelement of the three-element set {(x), (y), (x, y)}. In other words, “xand/or y” means “one or both of x and y”. As another example, “x, y,and/or z” means any element of the seven-element set {(x), (y), (z), (x,y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and/or z” means“one or more of x, y and z”. As utilized herein, the term “exemplary”means serving as a non-limiting example, instance, or illustration. Asutilized herein, the terms “e.g.,” and “for example” set off lists ofone or more non-limiting examples, instances, or illustrations. Asutilized herein, circuitry is “operable” to perform a function wheneverthe circuitry comprises the necessary hardware and code (if any isnecessary) to perform the function, regardless of whether performance ofthe function is disabled or not enabled (e.g., by a user-configurablesetting, factory trim, etc.).

While the present method and/or system has been described with referenceto certain implementations, it will be understood by those skilled inthe art that various changes may be made and equivalents may besubstituted without departing from the scope of the present methodand/or system. For example, block and/or components of disclosedexamples may be combined, divided, re-arranged, and/or otherwisemodified. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the presentdisclosure without departing from its scope. Therefore, the presentmethod and/or system are not limited to the particular implementationsdisclosed. Instead, the present method and/or system will include allimplementations falling within the scope of the appended claims, bothliterally and under the doctrine of equivalents.

What is claimed is:
 1. A weld circuit communications device, comprising:a receiver circuit configured to receive a communication via a weldcircuit while current is flowing through the weld circuit or after thecurrent has stopped flowing through the weld circuit, the communicationincluding weld voltage feedback information measured at a device remotefrom a power supply and remote from the weld circuit communicationsdevice while the current is flowing through the weld circuit; aprocessor configured to generate power supply control information basedon the weld voltage feedback information; and a local communicationsadapter comprising circuitry configured to transmit the power supplycontrol information to the power supply to control welding-type poweroutput by a power converter of the power supply to regulate a weldvoltage to a weld voltage setpoint, wherein the power supply is externalto the weld circuit communications device and is not capable ofcommunicating via the weld circuit, and the receiver circuit and thelocal communications adapter are configured to enable the power supplyto compensate an output of the power supply for a voltage drop in theweld circuit.
 2. The weld circuit communications device as defined inclaim 1, wherein the power supply control information includes at leastone of a voltage setpoint, a voltage error, or a weld cable impedance.3. The weld circuit communications device as defined in claim 1, furthercomprising a voltage monitor configured to measure a power supply outputvoltage, the weld voltage feedback information including a remotevoltage measured closer to the weld than the power supply output voltagemeasurement location.
 4. The weld circuit communications device asdefined in claim 1, further comprising a voltage monitor configured tomeasure a power source output voltage, the processor to generate thepower supply control information using the weld voltage feedbackinformation, the weld voltage setpoint, and the measured power sourceoutput voltage.
 5. The weld circuit communications device as defined inclaim 4, wherein the weld voltage feedback information comprises afiltered arc voltage of the welding-type power measured at a wire feederor a remote communications device, the voltage monitor is configured todetermine an filtered power supply output voltage of the welding-typepower measured at an output of the power supply, and the processor isconfigured to adjust a weld voltage of the welding-type power based on adifference between the filtered arc voltage and the filtered powersupply output voltage.
 6. The weld circuit communications device asdefined in claim 1, further comprising a transmitter configured totransmit weld information to the remote device via the weld circuitwhile the current is flowing through the weld circuit.
 7. The weldcircuit communications device as defined in claim 1, wherein the weldvoltage feedback information comprises a voltage error between thevoltage setpoint and a voltage measured at the device remote from thepower supply and remote from the weld circuit communications devicewhile the current is flowing through the weld circuit, the processorconfigured to generate the power supply control information using thevoltage error.
 8. The weld circuit communications device as defined inclaim 7, wherein the processor is configured to calculate an impedanceof a weld cable in the weld circuit using the voltage error, the powersupply control information comprising the impedance of the weld cable.9. The weld circuit communications device as defined in claim 1, whereinthe weld voltage feedback information comprises a voltage setpointcommand, the processor configured to provide the voltage setpointcommand for control of the power supply to output the welding-type powerhaving a voltage determined by the voltage setpoint command.
 10. A weldcircuit communications device, comprising: a voltage monitor comprisingcircuitry configured to measure a voltage of welding-type powertransmitted via a weld circuit during a welding-type operation; and atransmitter circuit configured to transmit, via the weld circuit duringtransmission of the welding-type power over the weld circuit, weldvoltage feedback information based on the voltage of the welding-typepower, wherein the weld circuit communications device is external to awire feeder that is coupled to the weld circuit, the wire feeder is notcapable of communicating via the weld circuit, and the voltage monitorand the transmitter are configured to enable a power supply providingthe welding-type power to the weld circuit to compensate an output ofthe power supply for a voltage drop in the weld circuit.
 11. The weldcircuit communications device as defined in claim 10, further comprisinga local communications adapter configured to receive a voltage setpointfrom a welding device.
 12. The weld circuit communications device asdefined in claim 11, further comprising a processor configured todetermine a voltage setpoint command based on a voltage setpoint and thevoltage, the transmitter circuit configured to transmit the voltagesetpoint command via the weld circuit.
 13. The weld circuitcommunications device as defined in claim 11, wherein the transmittercircuit is configured to transmit the voltage setpoint via the weldcircuit during transmission of the welding-type power over the weldcircuit.
 14. The weld circuit communications device as defined in claim11, further comprising a processor configured to determine an impedanceof a weld cable in the weld circuit based on the voltage setpoint, thevoltage, and a current of the welding-type power, the transmittercircuit configured to transmit the impedance via the weld circuit. 15.The weld circuit communications device as defined in claim 11, furthercomprising a processor configured to determine a voltage error as adifference between the voltage setpoint and the voltage, the transmittercircuit to transmit the voltage error via the weld circuit.
 16. A weldcircuit communications device, comprising: a local communicationsadapter comprising circuitry configured to receive weld voltage feedbackinformation from a welding device on a first interface; and atransmitter circuit configured to transmit, via a weld circuit duringtransmission of welding-type power over the weld circuit, the weldvoltage feedback information based on the voltage of the welding-typepower, wherein the welding device is external to the weld circuitcommunications device and is not capable of communicating via the weldcircuit, and the transmitter and the local communications adapter areconfigured to enable the welding device to transmit the weld voltagefeedback information to a power supply coupled to the weld circuit tocompensate an output of the power supply for a voltage drop in the weldcircuit.
 17. The weld circuit communications device as defined in claim16, wherein the local communications adapters is configured to receive avoltage measurement, the weld circuit communications device furthercomprising a processor configured to generate the weld voltage feedbackinformation from the voltage measurement.
 18. The weld circuitcommunications device as defined in claim 16, wherein the localcommunications adapter is configured to receive a voltage setpoint fromthe welding device and the transmitter circuit is configured to transmitthe voltage setpoint via the weld circuit during transmission of thewelding-type power over the weld circuit.
 19. The weld circuitcommunications device as defined in claim 16, wherein the localcommunications adapter is configured to receive a voltage setpoint fromthe welding device, the weld circuit communications device furthercomprising a processor configured to determine a voltage error as adifference between the voltage setpoint and the voltage, the transmittercircuit to transmit the voltage error via the weld circuit.
 20. The weldcircuit communications device as defined in claim 18, further comprisinga processor configured to determine an impedance of a weld cable in theweld circuit based on the voltage setpoint, the voltage, and a currentof the welding-type power, the transmitter circuit configured totransmit the impedance via the weld circuit.